JPH0415941Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to an intake port structure for an internal combustion engine.

[Conventional technology]

It is effective to use a helical intake port to generate a strong swirling flow within the combustion chamber. However, when such a helical intake port is used, there is a problem in that high filling efficiency cannot be obtained because the intake resistance becomes large when the engine is operated at high speed and under high load. Therefore, an intake control valve is installed in the intake passage, which changes the flow path of the intake air to generate a strong swirling flow inside the combustion chamber during low-load engine operation, and to obtain high charging efficiency during high-speed, high-load engine operation. Various internal combustion engines are known.

However, when such an intake control valve is used, a control device for the intake control valve is required in addition to the intake control valve, resulting in a complicated structure. Therefore, in order to generate a strong swirling flow without using an intake control valve and to ensure a certain degree of charging efficiency, a pair of intake valves is provided. An internal combustion engine is known that generates a swirling flow and generates a weak swirling flow that swirls in the same direction in the combustion chamber by the intake air flowing in from the other intake valve (Japanese Utility Model Publication No. 142330/1983). reference).

[Problem that the invention attempts to solve]

However, if we try to give a swirling flow to the intake air flowing in from either intake valve, the structure of the intake port will inevitably have a structure with a large inflow resistance, and this will result in a high filling rate when the engine is operated at high speeds and under high loads. The problem is that efficiency is difficult to obtain.

[Means for solving problems]

In order to solve the above problems, according to the present invention, each cylinder is equipped with a first intake valve and a second intake valve, and a common intake valve is provided from the outer wall surface of the cylinder head toward the first intake valve and the second intake valve. The passage extends, and the first intake valve and the second intake valve are arranged on both sides of a vertical plane including the cylinder axis and perpendicular to the outer wall surface of the cylinder head, and the passage extends from between the first intake valve and the second intake valve. A separation wall extending upstream of the intake passage along the above-mentioned vertical plane separates the intake passage into a first straight port toward the first intake valve and a second straight port toward the second intake valve.
The first straight port is divided into two straight ports, and the axis of the first straight port and the axis of the second straight port are inclined in the same direction with respect to the above-mentioned vertical plane.
The angle of inclination of the straight port axis with respect to the vertical plane is larger than the angle of inclination of the second straight port axis with respect to the vertical plane, and the first intake air flowing inside the first straight port along the first straight port axis is directed toward the periphery of the combustion chamber. The second intake air that flows into the combustion chamber toward the direction of the combustion chamber and also flows inside the second straight port along the second straight port axis is closer to the cylinder than the first intake air on the side opposite to the inlet position of the first intake air with respect to the cylinder axis. In an internal combustion engine where intake air flows into the combustion chamber on the side closer to the axis, the inflow axis of the intake air flowing into the combustion chamber from the second straight port is the upper part of the side wall surface of the second straight port on the side away from the first straight port. The first straight port is bulged along the axis, and the cross-sectional area of the first straight port is larger than the cross-sectional area of the second straight port.

〔Example〕

Referring to FIGS. 1 to 3, 1 is the cylinder head, 2 is the combustion chamber, 3 is the first intake valve, and 4 is the second intake valve.
Intake valves 5 indicate common intake passages extending from the cylinder head outer wall surface 6 toward the first intake valve 3 and the second intake valve 4, respectively. The first intake valve 3 and the second intake valve 4 are arranged on both sides of a vertical plane 8 that includes the cylinder axis 7 and is perpendicular to the cylinder head outer wall surface 6. distance a
The first intake valve 3 and the second intake valve 4 are arranged such that the distance b from the vertical surface 8 to the center of the valve body of the second intake valve 4 is longer than the distance b. A separation wall 9 is formed in the intake passage 5 and extends from between the first intake valve 3 and the second intake valve 4 along the vertical plane 8 toward the upstream side of the intake passage 5. A first straight port 10 extending substantially straight toward the intake valve 3 and a second straight port 11 extending substantially straight toward the second intake valve 4 are formed. The axis 12 of the first straight port 10 and the axis 13 of the second straight port 11 are inclined in the same direction with respect to the vertical plane 8, and the inclination angle α of the first straight port axis 12 with respect to the vertical plane 8 is Inclination angle β of port axis 13 with respect to vertical plane 8
larger than

the second on the side away from the first straight port 10;
The upper side wall surface of the straight port 11 is bulged toward the first straight port 10, and the inner wall surface of this bulged portion 14 is formed from a downwardly inclined surface 15. The lower end edge of this inclined surface 15 extends from the upper end of the side wall surface of the intake passage 5 upstream of the separation wall 9 to the second intake valve 4.
It extends to the inner wall surface of the second straight port 11 located substantially at the innermost part near the back surface of the bulk part. During this time, the inclined wall 15 has a substantially uniform inclination angle. When such a bulging portion 14 is not provided, the intake air flowing through the second straight port 11 flows into the combustion chamber 2 along the second straight port axis 13. However, when the bulging portion 14 is provided, the flow path of the intake air flowing into the combustion chamber 2 from the second straight port 11 is moved toward the cylinder axis 7 side as shown by arrow F. On the other hand, intake air flows from the first straight port 10 into the combustion chamber 2 along the first straight port axis 12 as shown by arrow G. The inclined wall 15 of the bulging portion 14 has a second
A flow path F for intake air flowing into the combustion chamber 2 from the straight port 11 is formed to pass through the cylinder axis 7. As shown in FIG. 3, the cross-sectional area of the first straight port 10 is larger than the cross-sectional area of the second straight port 11, and as shown in FIG. It has a diameter equal to or smaller than the diameter of the first intake valve 3.

As mentioned above, from the first straight port 10 and the second straight port 11 are flow paths G,
Intake air flows into the combustion chamber 2 along F. Furthermore, since the cross-sectional area of the first straight port 10 is larger than the cross-sectional area of the second straight port 11, the amount of intake air flowing into the combustion chamber 2 from the first straight port 10 is larger than that from the second straight port 11 into the combustion chamber. This amount is larger than the amount of intake air flowing into 2.
Incidentally, the strength of the swirling flow generated in the combustion chamber 2 is proportional to the magnitude of the rotational moment of the intake air, which is obtained by multiplying the distance from the cylinder axis 7 to the intake air flow path G by the amount of intake air. In the present invention, the intake air flowing into the combustion chamber 2 from the second straight port 11 has no rotational moment, so this intake air does not generate a swirling flow in the combustion chamber 2, but the first straight From port 10 to combustion chamber 2
The intake air flowing into the second straight port 1
The amount of intake air flowing into the combustion chamber 2 from the first straight port 10 is large compared to that of the intake air flowing into the combustion chamber 2 from the first straight port 10. Therefore, the intake air flowing from the first straight port 10 has a large rotational moment, so that a strong swirling flow is generated within the combustion chamber 2. It will be done. Also, which straight port 10, 1
1 is also formed from a straight port with the lowest flow resistance, so high filling efficiency can be obtained.

Another embodiment is shown in FIGS. 4 to 6. In this embodiment, the bulging portion 16 has a rectangular cross-sectional shape. In this embodiment as well, the bulging portion 16 has two straight ports 11 as in the embodiments shown in FIGS. 1 to 3.
A flow path F for intake air flowing into the combustion chamber 2 from the combustion chamber 2 is formed to pass through the cylinder axis 7.

[Effect of idea]

By using a pair of straight ports, high filling efficiency is ensured, and by forming a bulge in one of the straight ports, a strong swirling flow can be generated within the combustion chamber.

[Brief explanation of drawings]

Figure 1 is a plan sectional view of the cylinder head, Figure 2 is a sectional view taken along the - line in Figure 1, Figure 3 is a sectional view taken along the - line in Figure 1, and Figure 4 is a separate view. FIG. 5 is a cross-sectional view taken along the line -- in FIG. 4, and FIG. 6 is a cross-sectional view taken along the line -- in FIG. 4. 2... Combustion chamber, 3... First intake valve, 4... Second
Intake valve, 5...Intake passage, 6...Cylinder head side wall surface, 7...Cylinder axis, 8...Vertical surface, 9
...Separation wall, 10...First straight port, 1
1...Second straight port, 14, 16...Bulging portion.

Claims (1)

[Scope of utility model registration request] Each cylinder is equipped with a first intake valve and a second intake valve.
A common intake passage extends toward the intake valves, and the first intake valve and the second intake valve are arranged on both sides of a vertical plane that includes the cylinder axis and is perpendicular to the outer wall surface of the cylinder head. A separation wall extending from between the valve and the second intake valve toward the upstream side of the intake passage along the vertical plane transforms the intake passage into a first straight port toward the first intake valve and a second straight port toward the second intake valve. The axis of the first straight port and the axis of the second straight port are inclined in the same direction with respect to the vertical plane, and the angle of inclination of the first straight port axis with respect to the vertical plane is perpendicular to the axis of the second straight port. The first intake air flowing inside the first straight port along the axis of the first straight port is larger than the angle of inclination with respect to the plane, and the first intake air flows into the combustion chamber toward the periphery of the combustion chamber, and the second intake air flows along the axis of the second straight port. In an internal combustion engine in which the second intake air flowing in the straight port flows into the combustion chamber on the side opposite to the inflow position of the first intake air with respect to the cylinder axis and closer to the cylinder axis than the first air,
The upper part of the side wall surface of the second straight port on the side away from the first straight port is bulged out so that the inflow axis of intake air flowing into the combustion chamber from the second straight port passes through the cylinder axis. An intake port structure for an internal combustion engine in which the cross-sectional area is larger than the cross-sectional area of a second straight port.